the OC9 worked fine on the 10.5, with the stock weight and no headshell weight. If I recall correctly, I used a VTF of app. 2.0 - 2.1 grams.But I have a Koetsu Black installed now . The oc9 is with a friend now who also has an original classic with the standard arm.

It's been a while, but still enjoying the classic and the koetsu (albeit with new speakers and amplification).

But now I'm pondering whether or not to get a nordost wired junction box to go along with the armwand. The current junction box has the standard, colored, wiring... The Nordost Valhalla junction box costs some 350 dollar around here (Europe).